1.A 2.0 cm tall object is placed 15.0 cm in front of a convex lens. The focal le
ID: 1387169 • Letter: 1
Question
1.A 2.0 cm tall object is placed 15.0 cm in front of a convex lens. The focal length of the lens is 5.0 cm.
a) Calculate the image distance and image size (2pt).
b)Use the area below to construct a ray-diagram to locate the image. Be sure to indicate your scale, the image and its location (2pts)!
2. A 2.0 cm tall object is placed 15.0 cm in front of a concave lens. The focal length of the lens is 5.0 cm.
a) Calculate the image distance and image size (2pt).
b)Use the area below to construct a ray-diagram to locate the image. Be sure to indicate your scale, the image and its location (2pts)!
Explanation / Answer
1)
object distance, u = 15 cm
focal length, f = +5 cm (for convex lense f is always negative)
let v is the image distance
now, Apply 1/u + 1/v = 1/f
1/v = 1/f - 1/u
1/v = 1/(5) - 1/15
v = 7.5 cm <<<<<-------Answer
magnification,m = -v/u
= -(7.5)/15
= -0.5
image distance = m*object distance
= -0.5*2
= -1 cm <<<<<-------Answer
Here Image is real,invered and demagnified.
2)
object distance, u = 15 cm
focal length, f = -5 cm (for concave lense f is always negative)
let v is the image distance
now, Apply 1/u + 1/v = 1/f
1/v = 1/f - 1/u
1/v = 1/(-5) - 1/15
v = -3.75 cm <<<<<-------Answer
magnification,m = -v/u
= -(-3.75)/15
= 0.25
image distance = m*object distance
= 0.25*2
= 0.5 cm <<<<<-------Answer
Here Image is virtual,upright and demagnified.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.